The organizers could be the one to set up the music that goes in the headphones. This way, it won't need to play in the entire room. If you choose to have some kind of music, it could be from the Organizer's choice. If you think you would be distracted, you can choose to just not use any music.
I like your idea, except for the part where everyone is subjected to it. Which is why I think your idea could be implemented with headphones as the option, instead of music all around, like at Gym's or Swimming Pools.